Sodium-silicate composition.



UNITED STATES PATENT OFFICE.

JAMES G. VAIL, OF CHESTER, AND JOHN D. CARTER, OF LANSDOWNE,PENNSYLVANIA- SODIUM-SILICATE COMPOSITION.

No Drawing.

To all whom it may concern:

Be it known that we, JAMES G. VAIL and J OHN D. CARTER, both citizens ofthe United States, and residents of Chester, in the county of Delaware,State of Pennsylvania, and of- Lansdowne, in the county of Delaware,State of Pennsylvania, respectively, have invented certain new anduseful Improvements in Sodium-Silicate Compositions, of which thefollowing is a full, clear, and exact disclosure.

It is a fact that sodium silicate of the composition Na OSiO is achemical substance which is readily soluble in water. It

is also a fact that sodium silicates may be prepared with ahigherproportion of SiO than that indicated by the above formula, and,indeed, the proportion may be increased to the extent indicated in theformula Na O4SiO Commercially, it is possible to produce intermediateproducts of substantially any desired composition between these ratios.For the majority of commercial uses, those compositions con taming arelatively high proportion of silica are the more valuable or useful butwith those is found the disadvantage of diflicult solubility in water,requiring, in the case of anhydrous material, special apparatus and hightemperatures.

The present invention relates to a product consisting essentially ofsodium silicate, which is at the same time readily soluble in coldwater. Silicates of the types specified may be dried from solutions togive a product with a moisture content approximating in which conditionthey have the physical appearance of dryness, and are much more solublethan anhydrous material. We

have found, however, that by the addition of a suitable efliorescentsalt to a sodium silicate solution before drying, a product of greatlyincreased solubility may be prepared.

We do not wish to limit ourselves to the use of any specific efliorescent salt, as there are numerous ones which may, in greater or lessdegree, serve our purpose, but the preferred practice of our inventionconsists in adding to a solution of sodium silicate of approximately 40Baum (8.7% Na O, 28% SiO a quantity of sodium sulfate,

' either in anhydrous or crystal form, to the extent of 10% of theweight of silicate solution, if the dry sodium sulfate be used or anequivalent quantity of the crystals. So-

Specification of Letters Patent.

Patented May 18, 1915.

Application filed September 3, 1914. Serial No. 860,027.

dium sulfate crystals contain substantially 4.4% of sodium sulfate. TheWater is then evaporated off, in any suitable manner to produce a drypowder.

We are aware that it has been heretofore proposed to increase merely thesolubility of sodium silicate by adding thereto a delequescent salt,such as chlorid of sodium or similar salts, but the resultingcompositions all have the undesirable quality or property of beinggreatly affected by changing atmospheric conditions. The particlesadhere and form lumps or large solid masses which prohibit or greatlyinterfere with their use in the arts. Sodium sulfate, however, ispeculiarly adapted for the carrying out of this invention because of itsefllorescence and its tendency to create a balanced condition in thefinished product with respect to the absorption or loss of moisture.

One of the uses for which our new product is available is as aconstituent of dry cold water paint which is commercially dealt with ina powdered form. Another is for the familiar process of preserving eggsin a silicate of soda solution. Sodium sulfate has the further advantageof being neutral, and of producing no harmful effect in the processes inwhich silicate of soda is generally used. It further tends to produce aproduct which will not stick together on long standing, even in a humidatmosphere, a difficulty to which silicate of soda by itself ispeculiarly subject.

Among other salts which may be used in the place of sodium sulfate aresodium or potassium phosphate and potassium sulfate.

We desire it to be understood that in herein describing the finalproduct as a dry powder or composition, we have reference to itsphysical appearance, which is that of apparent or substantial dryness asd1st1nished from a damp or Wet material, and we, therefore, do not wishto be understood as thereby meaning that the product is entirely devoidof contained moisture.

Having thus described our invention what we claim and desire to protectby Letters Patent of the United States is 1. A dry water soluble sodiumsilicate composition containing sodium silicate and an efliorescent saltwhich does not react with sodium silicate.

2. A dry efiiorescent powder freely soluble in cold water and comprisingsodium silicate and sodium sulfate.

3. A. dry water soluble composition containing sodium silicate andsodium sulfate.

mew/e1 tively small proportion of sodium sulfate of a solution of sodiumsilicate and then evaporating the solution to an apparent dryness. 7.The method of producing a dry efliorescent cold water soluble sodiumsilicate composition Which consists in adding substantially 10% byweight of sodium sulfate solutioli to a sodium silicate solution, andthen evaporating the water out ofthe solution to apparent dryness.

In Witness whereof we have hereunto set our hands this first day ofSeptember 1914.

JAMES G. VAIL. JOHN D. CARTER. Witnesses:

HENRY W. JONES, GHAs. LONGBOTHAM.

